1. Field of the Invention
This invention pertains to apparatus and method for isolating fluids within the lens capsule in an eye from extracapsular tissues and intraocular fluids. More particularly, a sealing device adapted for placing inside a lens capsule and method for using the device are provided.
2. Description of Related Art
After removal of the human lens contents in ocular surgery, normal surgical procedure includes irrigation of the lens capsule to remove lens epithelial cells and lens fibers or cortex before implanting an intraocular lens (IOL). This procedure is called “polishing” the capsule. If all lens epithelial cells are not removed, they may cause posterior capsule opacification (PCO). PCO is the most common complication of cataract surgery and is a widespread cause of vision loss. Improved procedures for polishing the lens capsule before implanting an IOL are needed. There is a need to isolate the fluid used for capsule polishing (water or an aqueous solution of a chemical agent) from the exterior of the capsule. In other words, fluid communication from the interior to the exterior of the capsule should be eliminated, so that the tissues or intraocular fluids in the eye will not be affected by the polishing procedure. Effective and complete fluid isolation can make possible the use of even more effective polishing solutions. Techniques are being considered and may be developed in the future that depend even more critically on a complete removal from the interior of the capsule of any cells that may cause fibrosis or PCO.
Consideration is also being given to surgical techniques to improve vision in a phakic eye by techniques other than implantation of an IOL in the lens capsule. Some of these techniques involve reshaping or refilling the lens capsule for anatomical or optical (refractive) objectives by introducing liquids or gels into the lens capsule. For example, fluids may be developed for placement in a lens capsule to maintain elasticity of the capsule. Other fluids or materials may be developed to replace the natural lens contents with a material having a selected refractive index. In these cases, also, there is need to isolate the capsule from extracapsular tissues and intraocular fluids. Some of these techniques may also need a permanent membrane (artificial anterior capsule) to seal a capsulorhexis. Other surgical techniques that may benefit from apparatus and method for isolating fluid inside a capsule include: obtaining volumetric measurements of the intracapsular volume; expanding or reforming the capsular bag to aid in lens implantation, lens reposition or lens exchange; and removing secondary cataract pearls, fibrotic material or debris from the capsule, with or without lens implantation.
Recently the “Perfect Capsule™” device has become available for use during cataract surgery. Such device is disclosed in Pub. No. US2004/0010284 A1. This is a single use sterile capsule holding and sealing device used for irrigation of the capsular bag. The device includes a “vacuum” ring that may be activated by a vacuum syringe. The vacuum ring is oriented to seal against the anterior surface of the lens capsule. One or two ports in the device allow an irrigating solution to be injected or removed without contacting other internal structures of the eye after a seal between the device and the anterior surface is established. In one embodiment, the device includes a flexible “plug” that can be inserted through the incision and placed onto the exterior of the anterior surface of the capsule and around the capsulorhexis. In one embodiment, one tube is for aspiration of fluid and is attached to an aspiration port and a second tube communicates with a second port in the surface of the plug. The second tube and port may be omitted if irrigation and aspiration steps are performed sequentially. The device is molded from materials such as silicone or polyurethane such that it can be rolled into a form allowing it to pass through the normal incision into the anterior chamber of the eye.
While the Perfect Capsule™ affords a method to allow irrigation of the lens capsule without affecting other portions of an eye, there is a need for a sealing device and method to allow easier placement of the device during surgery. The device should allow observation of position and ready manipulation of position with respect to the capsulorhexis. Also, there is a need for a sealing device that can be used in other procedures to isolate fluids inside a lens capsule from tissues and fluids outside the capsule, either during surgery or for permanent placement.